thanks so much everyone! i was under the impression that ScanGauge would not work on my 2005 F350, at least it isn't listed on their web site as something that they support. i was looking at the AutoEnginuity tool instead.

no white yucky stuff. this truck has had an EGR delete done on it.
i am afraid that the stretched head bolts and plugged cooler/stuck turbo could be it. i hauled last year without any of these issues, these are new since May. we tow using the tow/haul mode, my husband was hauling yesterday and does drop to 3rd, i forget. not sure about speed though.

my husband will know, but since he isn't right here, what is "ect"?

thanks!